Many woodworking and other machines have a spindle rotating on an axis. This axis is used as a reference for setting the various tools guides and surfaces on the machine. On a table saw, a circular saw blade is mounted on the spindle. This blade is flat and lies in a plane at a right angle to the spindle axis. The table saw has a ferrous table with a saw slot therein. The saw blade extends up through the saw slot, to extend above the table surface. For most purposes, the table surface is at a right angle to the plane of the saw blade so that square cuts are made. The workpiece has a flat surface which lies against the plane of the table surface. Moving the workpiece past the blade makes the cut surface at a right angle to the table surface, as long as the spindle is positioned correctly. The surface of the ferrous saw table has a miter slot therein which is used to guide workpieces past the saw blade. Therefore, the direction of the miter slot must be parallel to the plane of the saw blade. In addition, the rip fence must be parallel to the plane of the blade. If the rip fence or the miter slot are not parallel to the plane of the blade, then the workpiece will be moved toward or away from the blade during the cut. This is undesirable for several reasons, including the fact that smooth cutting is not achieved. In addition, saw noise is increased. In other cases, the cut surfaces have burn marks from the saw blade. Another important reason is that there is a threat of kickback of the workpiece as it is being cut.
In the past, setting up the table saw has been very time-consuming and filled with a large amount of trial and error. The most successful alignment has been done by craftsmen who have had many years or experience. However, machinery of this type does not stay in adjustment because the machinery is hard-working and is subject to heavy loads and pounding from the lumber which it cross-cuts, rips or dados. There is need for tools which permit a craftsman who is skilled in woodworking but who is not skilled in machinery to adequately align and calibrate table saws to their optimum adjustment. The procedure must be easy to accomplish and must allow the operator to adjust and calibrate the saw quickly and accurately.
The prior U.S. Pat. No. 6,665,946 to Paul J. Reilly discloses a machine alignment system which aids in the alignment of the table surface at a right angle to the plane of the saw blade and relates the adjustment of the table so that the miter slot is parallel to the plane of the saw blade. It also discusses the problems of accurate engagement with the miter slot.